Method for AFC shields for multiple sensor magnetic transducers and magnetic transducers having multiple sensors and AFC shields

ABSTRACT

A method and system provide a magnetic transducer having an air-bearing surface (ABS). The method includes providing a first shield, a first read sensor, an antiferromagnetically coupled (AFC) shield that includes an antiferromagnet, a second read sensor and a second shield. The read sensors are between the first and second shields. The AFC shield is between the read sensors. An optional anneal for the first shield is in a magnetic field at a first angle from the ABS. Anneals for the first and second read sensors are in magnetic fields in desired first and second read sensor bias directions. The AFC shield anneal is in a magnetic field at a third angle from the ABS. The second shield anneal is in a magnetic field at a fifth angle from the ABS. The fifth angle is selected based on a thickness and a desired AFC shield bias direction for the antiferromagnet.

CROSS-REFERENCE TO RELATED PATENT APPLICATIONS

This application is a divisional of U.S. application Ser. No.15/219,474, filed on Jul. 26, 2016, which in turn is a divisional ofU.S. application Ser. No. 14/667,433, filed on Mar. 24, 2015, (now U.S.Pat. No. 9,431,031), the entireties of which are incorporated byreference herein.

BACKGROUND

FIG. 1 depicts an air-bearing surface (ABS) view of a conventional readtransducer 10. The conventional read transducer 10 includes shields 12and 20, sensor 14 and magnetic bias structures 16. The read sensor 14 istypically a giant magnetoresistive (GMR) sensor or tunnelingmagnetoresistive (TMR) sensor. The read sensor 14 includes anantiferromagnetic (AFM) layer, a pinned layer, a nonmagnetic spacerlayer, and a free layer. Also shown is a capping layer. In addition,seed layer(s) may be used. The free layer has a magnetization sensitiveto an external magnetic field. Thus, the free layer functions as asensor layer for the magnetoresistive sensor 14. The magnetic biasstructures 16 may be hard bias structures or soft bias structures. Thesemagnetic bias structures are used to magnetically bias the sensor layerof the sensor 14.

Although the conventional magnetic recording transducer 10 functions,there are drawbacks. In particular, the conventional magnetic recordingtransducer 10 may not function adequately at higher recording densities.Two-dimensional magnetic recording (TDMR) technology may enablesignificantly higher recording densities. In TDMR, multiple read sensorsare used. These sensors are longitudinally distributed along the crosstrack direction. The central sensor reads the data from a track ofinterest, while the outer sensors sense the data in adjacent tracks inorder to account for noise.

Although TDMR might be capable of higher recording densities, issues maycomplicate fabrication of a read transducer or adversely affect itsperformance. Fabrication of an additional read sensor above the readsensor 14 shown, in place of the shield 20, may be complicated. Further,the shields 12 and 20 and the magnetic bias structures 16 are desired tobe biased. The free layers of the read sensors are also magneticallybiased in a different direction from the shields and magnetic biasstructures. Providing the desired magnetic biasing of the shields andread sensors may be difficult to accomplish. Consequently, a transducersuitable for use in TDMR is desired.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 depicts a conventional read transducer.

FIG. 2A-2C depict side, ABS and plan views an exemplary embodimentportions of a disk drive.

FIG. 3 depicts an ABS view of another exemplary embodiment of a portionof a magnetic recording read transducer including multiple read sensors.

FIG. 4 depicts an ABS view of another exemplary embodiment of a portionof a magnetic recording read transducer including multiple read sensors.

FIG. 5 depicts an ABS view of another exemplary embodiment of a portionof a magnetic recording read transducer including multiple read sensors.

FIG. 6 is a flow chart depicting an exemplary embodiment of a method forfabricating a magnetic recording read transducer including multiple readsensors.

FIG. 7 is a flow chart depicting another exemplary embodiment of amethod for fabricating a disk drive including a magnetic recording readtransducer including multiple read sensors.

FIG. 8 is a graph depicting an exemplary embodiment of the bias angleversus antiferromagnetic layer thickness.

FIG. 9 is a flow chart depicting another exemplary embodiment of amethod for fabricating an antiferromagnetically coupled shield in amagnetic recording read transducer including multiple read sensors.

FIG. 10 is a flow chart depicting another exemplary embodiment of amethod for fabricating a magnetic recording read transducer includingmultiple read sensors.

FIGS. 11-16 depict wafer level views of an exemplary embodiment ofmagnetic field and bias directions for annealing in a magnetic field.

DETAILED DESCRIPTION

FIGS. 2A-2C depict side, ABS and plan views of a portion of a disk drive100. For clarity, FIGS. 2A-2C are not to scale. For simplicity not allportions of the disk drive 100 are shown. In addition, although the diskdrive 100 is depicted in the context of particular components otherand/or different components may be used. For example, circuitry used todrive and control various portions of the disk drive 100 is not shown.For simplicity, only single components are shown. However, multiples ofone or more of the components and/or their sub-components might be used.

The disk drive 100 includes media 101, a slider 102, a head 103including a write transducer 104 and a read transducer 110. The writetransducer includes at least a write pole 106 and coil(s) 108 forenergizing the pole 106. Additional and/or different components may beincluded in the disk drive 100. Although not shown, the slider 102, andthus the transducers 104 and 110 are generally attached to a suspension(not shown). The transducers 104 and 110 are fabricated on the slider102 and include an ABS proximate to the media 101 during use. Althoughboth a write transducer 104 and a read transducer 110 are shown, inother embodiments, only a read transducer 110 may be present. Further,multiple read and/or write transducers may be used. The read transducer110 includes multiple read sensors 112 and 114, shields 120 and 160 andmiddle shield(s) 130/150. In addition, magnetic bias structures 111 and116 for the sensors 112 and 114, respectively, are used.

The read transducer 110 includes multiple read sensors 112 and 114having sensor layers 113 and 115, respectively, that may be free layersin a giant magnetoresistive (GMR) sensor or a tunneling magnetoresistive(TMR) sensor. Thus, each sensor 112 and 114 may include a pinning layer,a pinned layer and a nonmagnetic spacer layer in addition to the freelayer 113 and 115, respectively. For simplicity, only the free layers113 and 115 are separately labeled. The sensors 112 and 114 may alsoinclude other layers such as seed layer(s) (not shown) and cappinglayer(s) (not shown). The pinning layer is generally an AFM layer thatis magnetically coupled to the pinned layer. In other embodiments,however, the pinning layer may be omitted or may use a different pinningmechanism. The free layers 113 and 115 are each shown as a single layer,but may include multiple layers including but not limited to a syntheticantiferromagnetic (SAF) structure. The pinned layer may also be a simplelayer or a multilayer. Although shown as extending the same distancefrom the ABS in FIG. 2A, the pinned layer may extend further than thecorresponding free layer 113 and/or 115. The nonmagnetic spacer layermay be a conductive layer, a tunneling barrier layer, or other analogouslayer. Although depicted as a GMR or TMR sensor, in other embodiments,other structures and other sensing mechanisms may be used for thesensor. In other embodiments, however, other sensors may be used. Forexample, the sensor 112 and/or 114 may employ a dual free layer schemein which two free layers that are biased in a scissor stated areutilized.

The read sensors 112 and 114 may have different widths in the trackwidth, or cross-track, direction. However, in other embodiments, thewidths of the sensors 112 and 114 may be the same. The widths of thesensors 112 and 114 may also be based on the track pitch. In theembodiment shown, the read sensors 112 and 114 are offset in the crosstrack direction. Therefore, the centers of each of the read sensors 112and 114 are not aligned along a line that runs the down track direction.In other embodiments, the read sensors 112 and 114 might be aligned. Theread sensor 114 is also in a down track direction from the read sensor112. The read sensor 114 is thus closer to the trailing edge of theslider 102 than the read sensor 112 is.

Also shown are bias structures 111 and 116 that magnetically bias theread sensors 112 and 114, respectively. The magnetic bias structure(s)111 and/or 116 may be soft bias structures fabricated with soft magneticmaterial(s). In other embodiments, the magnetic bias structure(s) 111and/or 116 may be hard magnetic bias structures. In still otherembodiments, the magnetic bias structure(s) 111 and/or 116 may have bothmagnetically hard and magnetically soft regions. Other mechanisms forbiasing the sensors 112, and 114 might also be used.

The read sensors 112 and 114 are separated by middle shield(s) 130/150.In embodiments in which only a single middle shield is used, then theinsulator 140 may be omitted. The read sensors 112 and 114 and shield130 are surrounded by first (bottom) shield 120 and second (top) shield160. In the embodiment shown in FIGS. 2A-2C, there are two read sensors112 and 114 and two middle shields 130 and 150. However, in anotherembodiment, another number of read sensors and middle/internal shieldsmay be present. The middle shield 130 might be considered to be a topmiddle shield because it is closest to and may be electrically coupledwith the top of the sensor 112. The middle shield 150 may be a bottommiddle shield because it is closest to and may be electrically coupledwith the bottom of the sensor 114.

The bottom middle shield 150 is a monolithic shield. In the embodimentshown, the bottom middle shield 150 includes a single typically softmagnetic layer. In other embodiments, multiple material(s) and/or layersmay be used. For example, the bottom middle shield 150 may include aNiFe layer and/or a CoFe layer.

The top middle shield 130 is an antiferromagnetically coupled (AFC)shield. The AFC middle shield 130 includes multiple magnetic layers 132and 136 separated by a nonmagnetic layer 134 and magnetically coupled toan antiferromagnetic (AFM) layer 138. Although not shown, seed and/orcapping layer(s) may be used. The magnetic layers 132 and 136 areantiferromagnetically coupled, typically via aRuderman-Kittel-Kasuya-Yosida (RKKY) interaction. The ferromagneticlayers 132 and/or 134 may include multiple sublayers. For example, thebottom ferromagnetic layer 132 may include a thin amorphous layer 131,such as a CoFeB insertion layer. In some embodiments, the bottom layer132 consists of NiFe layers separated by a thin CoFeB insertion layer131 and topped by a CoFe layer. For example the bottom layer may includeat least two hundred and not more than three hundred Angstroms of NiFetopped by not more than ten Angstroms of CoFeB, at least twenty-fiveAngstroms and not more than thirty five Angstroms of NiFe and at leastfive and not more than fifteen Angstroms of CoFe closest to thenonmagnetic layer 134. However other thicknesses and materials may bepresent. The top ferromagnetic layer 136 may include multiple magneticlayers. For example, the top ferromagnetic layer 136 may include CoFelayers separated by a NiFe layer. For example, the ferromagnetic layer136 may consist of at least five and not more than fifteen Angstroms ofCoFe, at least two hundred and not more than three hundred Angstroms ofNiFe and topped by at least fifteen and not more than twenty fiveAngstroms of CoFe. However, other thicknesses and other materials may beused. An amorphous magnetic layer such as the CoFeB insertion layer 131discussed above might also be used in the ferromagnetic layer 136. Useof the thin CoFeB insertion layer 131 within the layer 132 and/or 126may be desired to improve the thermal stability of the AFC shield 130.

The nonmagnetic layer 136 has a thickness configured to be within anantiferromagnetic coupling peak (in a plot magnetic coupling versusthickness) of the RKKY interaction. In some embodiments, the nonmagneticlayer 136 is within the first antiferromagnetic peak of the RKKYinteraction. In other embodiments, the nonmagnetic layer 136 is withinthe second antiferromagnetic peak of the RKKY interaction. In somecases, the second antiferromagnetic peak of the RKKY interaction ispreferred for thermal stability of the shield 130. The nonmagnetic layer136 includes conductive nonmagnetic material(s) for which the layers 132and 136 may be antiferromagnetically coupled. For example, thenonmagnetic layer 136 may consist of Ru and may have a thickness of atleast three and not more than ten Angstroms.

The AFM layer 138 is used to bias the magnetic moment of theferromagnetic layer 136. For example, the AFM layer 138 may includeIrMn. Thus, the AFM layer 138 may be thick enough to pin the magneticmoment of the ferromagnetic layer 136. In addition, the thickness of theAFM layer 138 may also be set to improve manufacturability of thetransducer 110. For example, the AFM layer 138 may also be sufficientlythin that the direction of the moments within the AFM layer 138 (i.e.the direction in which the spins are aligned parallel and antiparallel)may be set at an anneal temperature that is lower than the annealtemperature used for the sensors 112 and 114. For example, in someembodiments, one or more of the anneal(s) used in fabricating thesensor(s) 112 and/or 114 utilizes temperatures in excess of 270 degreesCelsius. Thus, the thickness of the AFM layer 138 may be set such thatan anneal of not more than 240 degrees Celsius can be used to set thedirection of the moments in the AFM and, therefore, the bias directionfor the ferromagnetic layer 136. In some embodiments, anneals of notmore than 220 degrees Celsius may be used to set the direction of themoments in the AFM layer 138. The thickness of the AFM layer 138 maythus be set such that fabrication/annealing for the AFC shield 130 doesnot adversely affect the read sensor(s) 112 and/or 114, so that theanneal for the AFC shield 130 may set the direction at which the layer136 is magnetically biased and such that the AFC shield 130 is stableduring operation of the transducer 110. In some embodiments, the AFMlayer 138 has a thickness of not more than one hundred sixty Angstroms.In some such embodiments, the AFM layer 138 has a thickness of not morethan one hundred Angstroms.

In the embodiment shown, the second (top) shield 160 is also an AFCshield. The second AFC shield 160 includes multiple magnetic layers 162and 166 separated by a nonmagnetic layer 164 and magnetically coupled toan AFM layer 168. Although not shown, seed and/or capping layer(s) maybe used. The magnetic layers 162 and 166 are antiferromagneticallycoupled, typically via the RKKY interaction. The ferromagnetic layers162 and/or 164 may include multiple sublayers. For example, layer 162may be analogous to the layer 132, while the layer 166 may be analogousto the layer 136. Thus, the bottom layer 162 may include NiFe layersseparated by a thin CoFeB insertion layer 161 and topped by a CoFe layerthat may all be in the thickness ranges described above. The topferromagnetic layer 166 may include CoFe layers separated by a NiFelayer that may be in the thickness ranges discussed above. In otherembodiments, other and/or additional materials may be used for thelayers 162 and/or 166. The nonmagnetic layer 164 may be analogous to thelayer 134. For example, the nonmagnetic layer 164 may have a thicknesswithin the first or second antiferromagnetic peak of the RKKYinteraction. The AFM layer 168 may be thick enough to pin the magneticmoment of the ferromagnetic layer 166, thin enough to have the magneticmoment direction set with anneal(s) that do not adversely affect thesensor(s) 112 and 114, thick enough that the top shield 160 is stableduring operation and may include IrMn.

In the embodiment shown the first (bottom) shield 120 and the bottommiddle shield 150 are monolithic shields. The top middle shield 130 andsecond (top) shield 160 are AFC shields. It may be desirable for theshields surrounding the sensors 112 and 114 to be configured similarly.For example, if the bottom middle shield 150 were an AFC shield, thenthe first (bottom) shield 120 may be desired to be an AFC shield. Thus,although the shields 120, 130, 150 and 160 are shown as having aparticular structure (monolithic or AFC), in other embodiments, thestructure might be different.

During fabrication, the magnetic transducer 110 undergoes variousanneals in order to set the magnetization/magnetic bias directions ofvarious magnetic components of the transducer 110. FIG. 2C depictsembodiments of some of the magnetic biases. The read sensors 112 and 114may be magnetically biased in the same direction. For example, the readsensors are generally biased perpendicular to the ABS. Thus, the stablestates of the magnetic moments of the free layers 113 and 115 may beperpendicular to the ABS. The top middle shield 130 and/or the second(top) shield 160 may also be desired to be magnetically biased in aparticular direction. For example, the middle shield 130 and/or thesecond shield 160 may be desired to be bias at an angle, .alpha., fromthe ABS. This angle may be at least zero degrees and not more thanfifty-five degrees from the ABS. In some embodiments, .alpha. is notmore than forty-five degrees from the ABS. In some such embodiments,.alpha. is at least thirty degrees and not more than forty degrees fromthe ABS. Note that the magnetic field with which the transducer 110 isannealed to set the direction of the AFM layer 138/168 spin duringfabrication may point in a direction other than at the angle .alpha.from the ABS. The direction of the magnetic field used is set based atleast upon the desired angle, .alpha., the thicknesses of the AFM layers138 and 168 and the magnetic states of the AFM layers 138 and 168 beforethe anneal. Thus, the desired structure 110 may be obtained.

In operation, current is driven perpendicular-to-plane for the sensors112 and 114. Thus, current is driven through the sensor 112 between theshields 120 and 130. Similarly, current is driven through the sensor 114between the shields 150 and 160. Thus, electrical connection is to bemade to the shields 120, 130, 150 and 160. However, different currentsmay be driven through the sensors 112 and 114 because of the presence ofthe insulator 140. Similarly, the resistances of the sensors 112 and 114may be separately sensed.

The magnetic read transducer 110 and disk drive 100 may have improvedperformance and manufacturability. Because multiple sensors 112 and 114employed, the magnetic transducer 110 may then be used at higher datarates and/or densities in TDMR. The desired magnetic biasing of thesensors 112 and 114 and shields 120, 130, 150 and 160 and the biasstructures 111 and 116 may also be accomplished. The presence of theamorphous CoFeB insertion layer 131/161 in the layer 132 and/or 162 mayimprove the thermal stability of the AFC shield(s) 130 and/or 160.Configuration of the thickness of the nonmagnetic layer 134/164, forexample to be in the second antiferromagnetic peak in the RKKYinteraction, may also improve thermal stability of the AFC shield(s) 130and/or 160. Performance and fabrication of the magnetic transducer 110may, therefore, be improved.

FIG. 3 depicts an ABS view of an exemplary embodiment of a transducer110′ that is part of a disk drive 100′. For clarity, FIG. 3 is not toscale. For simplicity not all portions of the disk drive 100′ andtransducer 110′ are shown. The transducer 110′ and disk drive 100′depicted in FIG. 3 are analogous to the read transducer 110 and diskdrive 100 depicted in FIGS. 2A-2C. Consequently, analogous componentshave similar labels. For simplicity, only a portion of the transducer110′ and disk drive 100′ are shown in FIG. 3.

The transducer 110′ includes first shield 120, read sensors 112 and 114,magnetic bias structures 111 and 116, AFC (top) middle shield 130,insulator 140, bottom middle shield 150′ and second shield 160 that areanalogous to the first shield 120, read sensors 112 and 114, magneticbias structures 111 and 116, and AFC (top) middle shield 130, insulator140, top middle shield 150 and second shield 160 depicted in FIGS.2A-2C, respectively. The transducer 110′ thus operates in a similarmanner to the transducer 110. Thus the top middle shield 130 includesamorphous layer 131, magnetic layer 132, nonmagnetic layer 134, magneticlayer 136 and AFM layer 138 that are analogous to amorphousferromagnetic layer 131, ferromagnetic layer 132, nonmagnetic layer 134,ferromagnetic layer 136 and an AFM layer 138, respectively, in FIGS.2A-2C. Other layers could also be included in the AFC shield 130.Similarly, second (AFC) shield 160 includes amorphous layer 161,magnetic layer 162, nonmagnetic layer 164, magnetic layer 166 and AFMlayer 168 that are analogous to amorphous magnetic layer 161, magneticlayer 162, nonmagnetic layer 164, magnetic layer 166 and AFM layer 168,respectively, in FIGS. 2A-2C.

In the embodiment shown, the bottom middle shield 150′ is an AFC coupledshield instead of a monolithic shield. Thus, the bottom middle shield150′ includes multiple magnetic layers 152 and 156 separated by anonmagnetic layer 154 and magnetically coupled to an AFM layer 158.Although not shown, seed and/or capping layer(s) may be used. Themagnetic layers 152 and 156 are antiferromagnetically coupled, typicallyvia an RKKY interaction. The ferromagnetic layers 152 and/or 154 mayinclude multiple sublayers. For example, the bottom layer 152 mayinclude a thin amorphous layer 151, such as a CoFeB insertion layer. Insome embodiments, the bottom layer 152 consists of NiFe layers separatedby a thin CoFeB insertion layer 151 and topped by a CoFe layer. The topferromagnetic layer 156 may include CoFe layers separated by a NiFelayer. The thicknesses and layers used may thus be analogous to thoseused for the AFC shields 130 and 160. However, other thicknesses andother materials may be used. The AFM layer 158 may be thick enough topin the magnetic moment of the ferromagnetic layer 156, thin enough thatthe anneal that sets the direction of the magnetic moments for the AFMlayer 158 does not adversely affect the sensor 112 and sufficientlythick that the transducer 110′ is stable during operation. For example,the AFM layer 158 may include IrMn.

The nonmagnetic layer 156 has a thickness configured to be within anantiferromagnetic coupling peak (in a plot magnetic coupling versusthickness) of the RKKY interaction. In some embodiments, the nonmagneticlayer 156 is within the first antiferromagnetic peak of the RKKYinteraction. In other embodiments, the nonmagnetic layer 156 is withinthe second antiferromagnetic peak of the RKKY interaction. In somecases, the second antiferromagnetic peak of the RKKY interaction ispreferred. The nonmagnetic layer 156 includes conductive nonmagneticmaterial(s) for which the layers 152 and 156 may beantiferromagnetically coupled. For example, the nonmagnetic layer 156may consist of Ru and may have a thickness of at least three and notmore than ten Angstroms. In the embodiment shown, the AFC shield 150′ isa bottom middle shield and different from the first (bottom) shield 120,which is monolithic. In some embodiments, however, the shields 120 and150′ are desired to match. Thus, the first shield 120 might also be anAFC shield. The AFC shields 130, 150′ and 160 are biased, annealed andconfigured in an analogous manner to the AFC shields 130 and 160discussed above.

The magnetic read transducer 110′ and disk drive 100′ shares thebenefits of the transducer 110 and disk drive 100. Thus, the transducer110′ may have improved performance and manufacturability.

FIG. 4 depicts an ABS view of an exemplary embodiment of a transducer110″ that is part of a disk drive 100″. For clarity, FIG. 4 is not toscale. For simplicity not all portions of the disk drive 100″ andtransducer 110″ are shown. The transducer 110″ and disk drive 100″depicted in FIG. 4 are analogous to the read transducer 110/110′ anddisk drive 100/100′ depicted in FIGS. 2A-2C and 3. Consequently,analogous components have similar labels. For simplicity, only a portionof the transducer 110″ and disk drive 100″ are shown in FIG. 4.

The transducer 110″ includes first shield 120, read sensors 112 and 114,magnetic bias structures 111 and 116, AFC (top) middle shield 130,insulator 140, bottom middle shield 150′ and second shield 160 that areanalogous to the first shield 120, read sensors 112 and 114, magneticbias structures 111 and 116, and AFC (top) middle shield 130, insulator140, top middle shield 150 and second shield 160 depicted in FIGS. 2A-3,respectively. The transducer 110″ thus operates in a similar manner tothe transducer 110. Thus the top middle shield 130 includes amorphouslayer 131, magnetic layer 132, nonmagnetic layer 134, magnetic layer 136and AFM layer 138 that are analogous to amorphous ferromagnetic layer131, ferromagnetic layer 132, nonmagnetic layer 134, ferromagnetic layer136 and an AFM layer 138, respectively, in FIGS. 2A-3. Other layerscould also be included in the AFC shield 130. Similarly, second (AFC)shield 160 includes amorphous layer 161, magnetic layer 162, nonmagneticlayer 164, magnetic layer 166 and AFM layer 168 that are analogous toamorphous magnetic layer 161, magnetic layer 162, nonmagnetic layer 164,magnetic layer 166 and AFM layer 168, respectively, in FIGS. 2A-3. Thebottom middle (AFC) shield 150′ includes amorphous layer 151, magneticlayer 152, nonmagnetic layer 154, magnetic layer 156 and AFM layer 158that are analogous to amorphous magnetic layer 151, magnetic layer 152,nonmagnetic layer 154, magnetic layer 156 and AFM layer 158,respectively, in FIGS. 2A-3.

In the embodiment shown in FIG. 4, the transducer 110″ includes anadditional sensor 118, an additional top middle shield 170, anadditional bottom middle shield 190 and an additional insulator 180. Theadditional sensor 118 is analogous to the sensors 112 and 114. Thus, theadditional sensor 118 may have a free layer 119 and is biased bymagnetic bias structures 117. In the embodiment shown, the middleshields 170 and 190 are AFC shields. The top middle shield 170 includesmultiple magnetic layers 172 and 176 separated by a nonmagnetic layer174 and magnetically coupled to an AFM layer 178. Although not shown,seed and/or capping layer(s) may be used. The bottom middle shield 190includes multiple magnetic layers 192 and 196 separated by a nonmagneticlayer 194 and magnetically coupled to an AFM layer 198. Although notshown, seed and/or capping layer(s) may be used. The AFC shields 170 and190 are analogous to the AFC shields 130, 150′ and 160. Thus, the layers171 and 191, 172 and 192, 174 and 194, 176 and 196 and 178 and 198 areanalogous to the layers 131/151/161, 132/152/162, 134/154/164,136/156/166, 138/158/168, respectively. However, in other embodiments,one or both of the shields 170 and 190 may be monolithic. Although thefirst shield 120 is shown as being monolithic, in another embodiment,the first shield 120 may be an AFC shield. Although all remainingshields 130, 150′, 160, 170 and 190 are shown in FIG. 4 as being AFCshields, in other embodiments, only some shields 130, 150, 160, 170and/or 190 are AFC shields. For example, in some embodiments, only thetop middle shields 130 and 170 and second (top) shield 160 are AFCcoupled shields. In such embodiments, the bottom middle shields 150′ and190 and first (bottom) shield 120 are monolithic shields. Such anembodiment may be preferred because the sensors 112, 114 and 118 aresurrounded by analogous structures. The AFC shields 130, 150′, 160, 170and 190 are biased, annealed and configured in an analogous manner tothe AFC shields 130, 150′ and 160 discussed above.

The magnetic read transducer 110″ and disk drive 100″ shares thebenefits of the transducer 110/110′ and disk drive 100/100′. Thus, thetransducer 110″ may have improved performance and manufacturability.

FIG. 5 depicts an ABS view of an exemplary embodiment of a transducer110′ that is part of a disk drive 100′″. For clarity, FIG. 5 is not toscale. For simplicity not all portions of the disk drive 100′″ andtransducer 110′″ are shown. The transducer 110′″ and disk drive 100′″depicted in FIG. 5 are analogous to the read transducer 110/110′/110″and disk drive 100/100′/100″ depicted in FIGS. 2A-2C, 3 and 4.Consequently, analogous components have similar labels. For simplicity,only a portion of the transducer 110′″ and disk drive 100′″ are shown inFIG. 5.

The transducer 110′″ includes first shield 120′, read sensors 112, 114and 118, magnetic bias structures 111, 116 and 117, top middle shields130 and 170, insulators 140 and 180, bottom middle shields 150 and 190′and second shield 160 that are analogous to the first shield 120, readsensors 112, 114 and 118, magnetic bias structures 111, 116 and 117, andtop middle shields 130 and 170, insulators 140 and 180, top middleshields 150/150′ and 190 and second shield 160 depicted in FIGS. 2A-4,respectively. The transducer 110′″ thus operates in a similar manner tothe transducer 110. The top middle shield 130 includes amorphous layer131, magnetic layer 132, nonmagnetic layer 134, magnetic layer 136 andAFM layer 138 that are analogous to amorphous ferromagnetic layer 131,ferromagnetic layer 132, nonmagnetic layer 134, ferromagnetic layer 136and an AFM layer 138, respectively, in FIGS. 2A-4. Other layers couldalso be included in the AFC shield 130. Similarly, second (AFC) shield160 includes amorphous layer 161, magnetic layer 162, nonmagnetic layer164, magnetic layer 166 and AFM layer 168 that are analogous toamorphous magnetic layer 161, magnetic layer 162, nonmagnetic layer 164,magnetic layer 166 and AFM layer 168, respectively, in FIGS. 2A-3. Thebottom middle shields 150 and 190′ are monolithic in the embodimentshown. Top middle shield 170 includes amorphous layer 171, magneticlayer 172, nonmagnetic layer 174, magnetic layer 176 and AFM layer 178that are analogous to amorphous magnetic layer 171, magnetic layer 172,nonmagnetic layer 174, magnetic layer 176 and AFM layer 178,respectively, in FIG. 4.

In the embodiment shown in FIG. 5, the first (bottom shield) 120′ is anAFC shield. Thus, the first shield 120′ includes multiple magneticlayers 122 and 126 separated by a nonmagnetic layer 124 and magneticallycoupled to an AFM layer 128. The AFC shield 120′ is analogous to the AFCshields 130, 150′, 170 and 160. Thus, the layers 121, 122, 124, 126 and128 are analogous to the layers 131/151/161/171/191,132/152/162/172/192, 134/154/164/174/194, 136/156/166/176/196,138/158/168/178/198, respectively. Although the first shield 120′ isshown as being an AFC shield, in another embodiment, the first shield120 may be a monolithic shield. Although shields 130, 160 and 170 areshown as being AFC shields, in other embodiments, only some shields 130,160 and/or 170 AFC shields. Similarly, although the shields 150 and 190′are shown as being monolithic, in other embodiments, one or both of theshield 150 and 190′ may be AFC shields. The AFC shields 120′, 130, 170and 160 are biased, annealed and configured in an analogous manner tothe AFC shields 130, 150′, 160, 170 and 190 discussed above.

The magnetic read transducer 110′″ and disk drive 100′″ shares thebenefits of the transducer 110/110′/110″ and disk drive 100/100′/100″.Thus, the transducer 110′″ may have improved performance andmanufacturability.

FIG. 6 is an exemplary embodiment of a method 200 for providing a readtransducer having multiple sensors. Some steps may be omitted,interleaved, and/or combined. For simplicity, the method 200 isdescribed in the context of providing a single recording transducer 110.However, other magnetic recording transducers 110′, 110″ and/or 110′″may be manufactured. Further, the method 200 may be used to fabricatemultiple transducers at substantially the same time. The method 200 mayalso be used to fabricate other transducers. The method 200 is alsodescribed in the context of particular layers. A particular layer mayinclude multiple materials and/or multiple sub-layers. The method 200also may start after formation of other portions of the magneticrecording transducer.

The first shield 120 is provided, via step 202. Step 202 typicallyincludes depositing (e.g. plating) a large high permeability layer. Inalternate embodiments, in which the shield 120 is an AFC shield, step202 includes depositing multiple ferromagnetic layers interleaved withand sandwiching at least one nonmagnetic layer and depositing an AFMlayer adjoining one of the ferromagnetic layers. The layer may also beplanarized.

The first read sensor 112 is provided, via step 204. Step 204 mayinclude full-film depositing an AFM layer, a pinned layer, a nonmagneticspacer (e.g. tunneling barrier) layer and a free layer 113. The readsensor 112 may also be defined in step 204. Step 204 may define the readsensor 112 in the cross track and/or the stripe height direction. Thestripe height direction is perpendicular to the ABS. The magnetic biasstructures 111 for the read sensor 112 may also be fabricated as part ofstep 204. Step 204 may also include annealing the portion of thetransducer that has been fabricated. The anneal may be used to set thedirection of magnetization of portions of read sensor stack and/or forother purposes. For example, the anneal may be in a magnetic field thatis in the direction in which the read sensor is desired to be biased. Insome embodiments, this direction is perpendicular to the ABS. Thisanneal may also be at a high temperature compared with the anneal(s) forthe shield(s) 120, 130, 150 and/or 160. In some embodiments, thetemperature for the anneal of the read sensor 112 is at least 250degrees Celsius. The temperature may be at least 270 degrees Celsius insome cases.

The top middle shield 130 is provided, via step 206. Thus, step 206generally includes providing an AFC shield. The ferromagnetic layers 132and 136 and the nonmagnetic layer 134 are deposited to the desiredthicknesses in step 206. As part of depositing the layer 132 and/or 136,an amorphous magnetic layer such as the CoFeB insertion layer 131 mayalso be deposited. Step 206 also includes depositing theantiferromagnetic layer 138 to the desired thickness.

An insulating layer 140 and an additional, bottom middle shield 150 mayalso be provided, via step 208. In some embodiments, the step 208 ofproviding the bottom middle shield 150 includes depositing a monolithicshield. In other embodiments, step 208 may include providing an AFCcoupled shield. In such embodiments, this portion of step 208 isanalogous to step 206.

The second read sensor 114 is provided, via step 210. Step 210 mayinclude full-film depositing an AFM layer, a pinned layer, a nonmagneticspacer (e.g. tunneling barrier) layer and a free layer 115. The readsensor 114 may also be defined in the cross track and/or the stripeheight direction. The magnetic bias structures 116 for the read sensor114 may also be fabricated as part of step 210. Step 210 may alsoinclude annealing the portion of the transducer that has been fabricatedto set the direction of magnetization of portions of read sensor stackand/or for other purposes. For example, the anneal performed in step 210may be analogous to the anneal for step 204.

Step 206, 208 and 210 may optionally be repeated a desired number oftimes, via step 212. Thus, a transducer, such as the transducer 110″and/or 110′″ having more than two read sensors may be fabricated.

The second shield 160 is provided, via step 214. Step 214 may includeproviding an AFC shield. Thus, step 214 may be performed in an analogousmanner to step 206. The ferromagnetic layers 162 and 166 and thenonmagnetic layer 164 are deposited to the desired thicknesses in step214. As part of depositing the layer 162 and/or 166, an amorphousmagnetic layer such as the CoFeB insertion layer 161 may also bedeposited. Step 214 also includes depositing the antiferromagnetic layer168 to the desired thickness.

At least one anneal is performed for the shield(s), via 216. Thus, theshields 120, 130, 150 and 160 as well as read sensors 112 and 114 areannealed in a magnetic field in step 216. The anneal performed in step216 is at temperature(s) and magnetic field(s) that are sufficientlyhigh to set the direction of the AFM layers' 138 and 168 moments and,therefore, the directions of magnetization for the layers 132, 136, 162and 166. The temperature(s) of the anneal are also sufficiently low thatthe read sensors 112 and 114 are not adversely affected.

The anneal performed in step 216 is in a magnetic field at an angle fromthe location/plane which will form the ABS after lapping (“ABSlocation”). This angle is selected based on a thickness and a desiredAFC shield bias direction for the AFM layer 138 and/or 168. The angle ofthe magnetic field is also selected such that the ADC shield(s) 130 and160 are biased in the desired AFC shield bias direction after the annealhas been completed. In some embodiments, the angle between the magneticfield direction and the ABS location is at least zero degrees and notmore than fifty-five degrees. In some cases, this angle is not more thanforty-five degrees from the ABS location. Although the magnetic fieldangle is selected in part based on the desired AFC shield biasdirection, the angle may be in a direction that is different from thedesired AFC shield bias direction. It is the combination of thethickness of the AFM layer(s) 138 and/or 168, the pre-anneal magneticstate of the AFM layer(s) 138 and/or 168 and the angle the magneticfield makes with the ABS location that allows the resulting shields 130and 160 to be magnetically biased in the desired AFC shield biasdirection.

For example, in some embodiments, the desired AFC shield bias directionmay be nominally thirty-five degrees from the ABS location. Thepre-anneal state of the AFC shield 130 and/or 160 may be magneticallybiased perpendicular to the ABS location because of the anneals of thesensors 112 and 114. This magnetic state may be due to the anneal of thesensor(s) in steps 204, 210 and, optionally, 212. The angle of themagnetic field during the anneal of step 216 may be at zero degrees forsome thicknesses of the AFM layers 138 and 168. For such thicknesses ofthe AFM layer(s) 138/168 and given the magnetic state of the AFM layer138/168 after the anneal(s) in steps 210 and 212, an anneal of thetransducer 110 in a magnetic field at zero degrees from the ABS locationresults in the AFC shield(s) 130/160 being biased at nominallythirty-five degrees from the ABS location. Thus, the magnetic fieldangle for the anneal in step 216 is based on the thickness of the AFMlayer 138/168 and may differ from the desired bias angle for themagnetic moments of the AFC shield(s) 130/160. Note that for somethicknesses of the AFM layer 138/168, however, the magnetic field anglemay match the desired bias angle.

Using the method 200, the magnetic read transducer 110 and disk drive100 may be provided. The transducers 110′, 110″ and/or 110′″ may also bemanufactured using the method 200. Because of the manner in which theanneals and other steps of the method 200 are performed, the desiredgeometry and magnetic properties of the transducers 110, 110′, 110″and/or 110′″ may be attained. The benefits of the transducers 110, 110′,110″ and/or 110′″ may thus be achieved.

FIG. 7 is an exemplary embodiment of a method 220 for providing a readtransducer having multiple sensors. Some steps may be omitted,interleaved, and/or combined. For simplicity, the method 220 is alsodescribed in the context of providing a single recording transducer 110.However, other magnetic recording transducers 110′, 110″ and/or 110′″may be manufactured. Further, the method 220 may be used to fabricatemultiple transducers at substantially the same time. The method 220 mayalso be used to fabricate other transducers. The method 220 is alsodescribed in the context of particular layers. A particular layer mayinclude multiple materials and/or multiple sub-layers. The method 220also may start after formation of other portions of the magneticrecording transducer.

The first shield 120 is provided, via step 222. Step 222 typicallyincludes depositing (e.g. plating) a large high permeability layer. Thelayer may also be planarized. In some embodiments, step 222 includesannealing the portion of the transducer 110 that has been fabricated.The anneal is at an elevated temperature and in a magnetic field. Themagnetic field is in a direction from the ABS location. However, inother embodiments, particularly if the first shield 120 is monolithic,this anneal might be omitted.

The first read sensor 112 is provided, via step 224. Step 224 may beanalogous to step 204. Thus, step 224 may include depositing the layersfor the sensor 112 and annealing the portion of the transducer 110 thathas been fabricated (including the sensor 112). The anneal may be usedto set the direction of magnetization of portions of read sensor stackand/or for other purposes. The anneal may be in a magnetic field that isin the direction in which the read sensor is desired to be biased, forexample perpendicular to the ABS. This anneal may also be at a hightemperature compared with the anneal(s) for the shield(s) 120, 130, 150and/or 160. In some embodiments, the temperature for the anneal of theread sensor 112 is at least 250 degrees Celsius. The temperature may beat least 270 degrees Celsius in some cases. The magnetic bias structures111 for the read sensor 112 may also be fabricated as part of step 224.

The top middle shield 130 is provided, via step 226. Thus, step 226includes providing an AFC shield. Step 226 is, therefore, analogous tostep 206. In addition, at least one AFC shield anneal is also performedas part of step 226. Thus, the portion of the transducer 110 that hasbeen formed is annealed in a magnetic field. The magnetic field is in adirection at an AFC shield anneal angle from the ABS location. This AFCshield anneal angle is at least zero degrees and not more thanfifty-five degrees from the ABS location. In some embodiments, themagnetic field is at an angle of nominally forty-five degrees from theABS location. The anneal performed in step 226 is at temperature(s) andmagnetic field(s) that are sufficiently high to set the direction of theAFM layer 138 spins and, therefore, the directions of magnetization forthe layers 132 and 136. The temperature(s) of the anneal are alsosufficiently low that the read sensor 112 is not adversely affected.

An insulating layer 140 and an additional, bottom middle shield 150 mayalso be provided, via step 228. In some embodiments, the step 228 ofproviding the bottom middle shield 150 includes depositing a monolithicshield. In other embodiments, step 228 may include providing an AFCcoupled shield. In such embodiments, this portion of step 228 isanalogous to step 226. An anneal may optionally be performed for thebottom middle shield 150.

The second read sensor 114 is provided, via step 230. Step 230 may beanalogous to step 210. The magnetic bias structures 116 for the readsensor 114 may also be fabricated as part of step 230. Step 230 may alsoinclude annealing the portion of the transducer that has been fabricatedto set the direction of magnetization of portions of read sensor stackand/or for other purposes. For example, the anneal performed in step 230may be analogous to the anneal for step 224.

Step 226, 228 and 230 may optionally be repeated a desired number oftimes, via step 232. Thus, a transducer, such as the transducer 110″and/or 110′″ having more than two read sensors may be fabricated.

The second shield 160 is provided, via step 234. Step 234 may includeproviding an AFC shield. Thus, step 234 may be performed in an analogousmanner to step 226. Step 234 also includes performing at least oneanneal. Thus, the shields 120, 130, 150 and 160 as well as read sensors112 and 114 are annealed in a magnetic field in step 234. The annealperformed in step 234 is at temperature(s) and magnetic field(s) thatare sufficiently high to set the direction of the AFM layers' 138 and168 moments and, therefore, the directions of magnetization for thelayers 132, 136, 162 and 166. The temperature(s) of the anneal are alsosufficiently low that the read sensors 112 and 114 are not adverselyaffected.

Like step 216 of the method 200, however, the anneal in step 234 is in amagnetic field at an angle from the ABS location. This angle is selectedbased on a thickness and a desired AFC shield bias direction for the AFMlayer 138 and/or 168. In some embodiments, this angle is at least zerodegrees and not more than fifty-five degrees from the ABS location. Insome embodiments, this angle is not more than forty-five degrees fromthe ABS location. The angle may be in a direction that is different fromthe desired AFC shield bias direction. Thus, the magnetic field anglefor the anneal in step 234 is based on the thickness of the AFM layer138/168 and may differ from the desired bias angle for the magneticmoments of the AFC shield(s) 130/160. Note that for some thicknesses ofthe AFM layer 138/168, however, the magnetic field angle may match thedesired bias angle.

Using the method 220, the magnetic read transducer 110 and disk drive100 may be provided. The transducers 110′, 110″ and/or 110′″ may also bemanufactured using the method 220. Because of the manner in which theanneals and other steps of the method 220 are performed, the desiredgeometry and magnetic properties of the transducers 110, 110′, 110″and/or 110′″ may be attained. The benefits of the transducers 110, 110′,110″ and/or 110′″ may thus be achieved.

Referring to FIGS. 6 and 7, the magnetic angles selected for the annealsin steps 216 and 232 depend upon the thickness of the AFM layer 138and/or 168 for the AFC shield(s) 130/160. This is indicated in FIG. 8,which is a graph 240 depicting the final bias angle, .alpha., versusthickness of the AFM layer 138/168 for a fixed magnetic field annealangle, As shown in FIG. 2C, the angle, a, is the angle between the ABS(or ABS location) and the final magnetic bias of the AFC shield130/150′/160/170/190. The angle 0 is the angle between the ABS locationand the magnetic field for the anneal of step 216 or step 232 of themethod 200 or 220, respectively. As can be seen in FIG. 8, the finalangle depends upon the thickness of the AFM layer 138, 158, 168, 178 or198. For all cases, it is assumed that the initial state of the AFCshield bias is perpendicular to the ABS because of the sensor anneal instep 210/212 or 230. For a large enough AFM layer thickness, the annealresults in a single bias angle that is closer to the initial state. Forthe middle range of thicknesses, which are typically of interest for AFCshields, the final bias angle depends upon the thickness of the AFMlayer. This final bias angle is generally between the initial angle(e.g. perpendicular to the ABS) and the angle of the anneal (0). Forvery small AFM layer thicknesses, the AFM layer 138, 158, 168, 178, or198 is less stable. Thus, the final bias angle is the same as the angleof the magnetic field during the anneal (.alpha.=.theta.). Similargraphs may be obtained for other magnetic field angles in the annealand/or other thicknesses of the AFM layers. Thus, as discussed above,the bias angle for the AFC shield(s) of the transducers 110, 110′, 110″and 110′″ may be set by the angle of the magnetic field during the AFCshield anneal. Further, the bias angle, and thus the magnetic fieldangle, may be selected based at least in part on the thickness of theAFM layers in the AFC shields.

FIG. 9 is an exemplary embodiment of a method 250 for providing an AFCshield in a read transducer having multiple sensors. Some steps may beomitted, interleaved, and/or combined. The method 250 is also describedin the context of providing the AFC shield 130 in the single recordingtransducer 110. However, other AFC shields and/or other magneticrecording transducers 110′, 110″ and/or 110′″ may be manufactured.Further, the method 250 may be used to fabricate multiple shields andmultiple transducers at substantially the same time. The method 250 mayalso be used to fabricate other transducers. The method 250 is alsodescribed in the context of particular layers. A particular layer mayinclude multiple materials and/or multiple sub-layers. The method 250also may start after formation of other portions of the magneticrecording transducer. The method 250 may be incorporated into the method200, 220 and/or 270 (discussed below).

The ferromagnetic layer 132 is provided, via step 252. In someembodiments, step 252 includes depositing an amorphous magneticinsertion layer within the ferromagnetic layer 132. For example, theCoFeB insertion layer 131 may be provided as part of step 252. Theferromagnetic layer 132 may also include other magnetic layers. Forexample, a NiFe/CoFeB/NiFe/CoFe layer may be deposited for the magneticlayer 132 in step 252.

The nonmagnetic layer 134 is provided, via step 254. Step 254 mayinclude depositing a nonmagnetic material, such as Ru, to a thicknesscorresponding to the first or second antiferromagnetic coupling peak inthe RKKY interaction. In some embodiments, the second antiferromagneticcoupling peak is selected.

The ferromagnetic layer 136 is provided, via step 256. In someembodiments, step 256 includes depositing an amorphous magneticinsertion layer within the ferromagnetic layer 136. The ferromagneticlayer 136 may also include other magnetic layers. For example, aCoFe/NiFe/CoFe layer may be deposited for the magnetic layer 136 in step256.

If more than two ferromagnetic layers are desired in the AFC shield,then steps 254 and 256 are optionally repeated a desired number oftimes. The antiferromagnetic layer 138 is deposited to the desiredthickness, via step 260. Using the method 250, the desired configurationof the AFC shield(s) 130, 150′, 160, 170 and/or 190 may be achieved. Thebenefits of the transducer(s) 110, 110′, 110″, and/or 110′″ may beattained.

FIG. 10 is an exemplary embodiment of another method 270 for providing aread transducer. Some steps may be omitted, interleaved, and/orcombined. FIGS. 11-16 depict wafer 300 level views of an exemplaryembodiments of a transducers that may be used in a magnetic disk driveduring fabrication using the method 270. The transducers being formedmay be considered to be analogous to the transducer 110′″, exceptincluding a monolithic lower shield 120 in lieu of the AFC lower shield120′. FIGS. 11-16 are not to scale and not all portions of thetransducer 300 are shown. However, the method 250 may be used tofabricate multiple transducers at substantially the same time. Themethod 250 may also be used to fabricate other disk drives including butnot limited to the disk drive 100 and transducers 110/110′/110″/110′″.The method 270 is also described in the context of particular layers. Aparticular layer may include multiple materials and/or multiplesub-layers. The method 270 also may start after formation of otherportions of the magnetic recording transducer.

The first shield 120 is provided, via step 272. Step 222 typicallyincludes depositing (e.g. plating) a large high permeability layer. Thelayer may also be planarized. In some embodiments, step 272 mayoptionally include annealing the portion of the transducer 110 that hasbeen fabricated. The anneal is at an elevated temperature and in amagnetic field. The magnetic field is in a direction at least zerodegrees and not more than fifty-five degrees from the ABS location.However, in other embodiments, this anneal might be omitted.

The first read sensor 112 is provided, via step 274. Step 274 may beanalogous to steps 204 and 224. Thus, step 274 may include depositingthe layers for the sensor 112 and annealing the portion of thetransducer 110 that has been fabricated (including the sensor 112). Theanneal may be used to set the direction of magnetization of portions ofread sensor stack and/or for other purposes. The anneal may be in amagnetic field that is in the direction in which the read sensor isdesired to be biased, for example perpendicular to the ABS. This annealmay also be at a high temperature compared with the anneal(s) for theshield(s) 120, 130, 150 and/or 160. In some embodiments, the temperaturefor the anneal of the read sensor 112 is at least 250 degrees Celsius.The temperature may be at least 270 degrees Celsius in some cases. Themagnetic bias structures 111 for the read sensor 112 may also befabricated as part of step 274

The top middle shield 130 is provided, via step 276. Thus, step 276includes providing an AFC shield. Step 276 is, therefore, analogous tosteps 206 and 226. FIG. 11 depicts the wafer 110 during step 276, afterdeposition of the layers 132, 134, 136 and 138 for the shield 130. Inthis case, the shield magnetic bias direction is parallel to the ABSlocation after deposition. An AFC shield anneal is also performed aspart of step 276. Thus, the portion of the transducer 110′″ that hasbeen formed is annealed in a magnetic field. FIG. 12 depicts the wafer300 after the anneal, as well as the direction of the magnetic fieldduring the anneal. The magnetic field is in a direction at an AFC shieldanneal angle, .theta.1, from the ABS location. This AFC shield annealangle .theta.1 is at least zero degrees and not more than fifty-fivedegrees from the ABS location. In some embodiments, .theta.1 isnominally forty-five degrees from the ABS location. The anneal performedin step 276 is at temperature(s) and magnetic field(s) that aresufficiently high to set the direction of the AFM layer 138 spins and,therefore, the directions of magnetization for the layers 132 and 136.The temperature(s) of the anneal are also sufficiently low that the readsensor 112 is not adversely affected. After the anneal, the biasdirection for the AFC shield 130 is at an angle .beta.1 from the ABSlocation.

An insulating layer 140 and an additional, bottom middle shield 150 areprovided, via step 278. In some embodiments, the step 228 of providingthe bottom middle shield 150 includes depositing a monolithic shield. Ananneal may optionally be performed for the bottom middle shield 150.However, in the embodiment shown, no anneal is performed.

The second read sensor 114 is provided, via step 280. Step 280 may beanalogous to steps 210 and 230. The magnetic bias structures 116 for theread sensor 114 may also be fabricated as part of step 280. Step 280 mayalso include annealing the portion of the transducer that has beenfabricated to set the direction of magnetization of portions of readsensor stack and/or for other purposes. For example, the annealperformed in step 280 may be analogous to the anneal for step 274. FIG.13 depicts the wafer after step 280 is performed. The direction of themagnetic field for the anneal is in the desired sensor bias direction:perpendicular to the Abs. Thus, the magnetic field direction for theanneal, .theta.2, is nominally ninety degrees. Because the sensor annealis at a higher temperature than the AFC shield anneal, the AFC shield130 bias direction is changed to match that of the magnetic field usedin step 280. Thus, the angle for the shield bias direction after step280, .beta.2, is nominally ninety degrees.

Steps 276, 278 and 280 may optionally be repeated a desired number oftimes, via step 282. In this embodiment, each step 276, 278 and 280 isrepeated once. Thus, an additional AFC shield 170, an additionalinsulator 180 and a monolithic bottom shield 190′ are provided. FIG. 14depicts the bias for the shields 130 and 170 after the anneal performedwhen step 276 is repeated. In the embodiment shown, the magnetic fielddirection is the same for both iterations of step 276. In other words,.theta.3=.theta.1. Consequently, the AFC shield bias direction, .beta.3is the same as .beta.1 (.beta.3=.beta.1). FIG. 15 depicts the wafer 300after step 278 has been repeated to form the sensor 118. Because thedesired sensor bias direction is perpendicular to plane and the annealis performed at a higher temperature, the shields 130 and 170 are againbiased nominally perpendicular to plane (.theta.4=.beta.4=90 degrees).

The second (top) shield 160 is provided, via step 284. Thus, step 284may be performed in an analogous manner to step 276. Step 284 alsoinclude performing at least one anneal. Thus, the shields 120, 130, 150,170, 190 and 160 as well as read sensors 112, 114 and 118 are annealedin a magnetic field in step 284. However, the angle of the magneticfield in step 284 may differ from that in steps 276 and 282. The annealperformed in step 232 is at temperature(s) and magnetic field(s) thatare sufficiently high to set the direction of the AFM layers' 138, 178and 168 moments. The temperature(s) of the anneal are also sufficientlylow that the read sensors 112 and 114 are not adversely affected. Inthis embodiment, the magnetic field direction during the anneal in step284 is not more than forty-five degrees from the ABS location. In someembodiments, the magnetic field is parallel to the ABS (e.g. in thecross-track direction). FIG. 16 depicts the wafer 300 after step 284.The magnetic field is at an angle of .theta.5. In the embodiment shownin FIG. 6, .theta.5 is zero degrees. The shield bias direction after theanneal, .beta.5, is the desired, final shield bias direction .alpha.This is not more than forty-five degrees from the ABS. In someembodiments, a is nominally thirty-five degrees.

Using the method 270, the desired biasing for the AFC shields 130, 170,and 160 may be achieved. The benefits of the transducers 110, 110′, 110″and/or 110′″ may thus be realized.

What is claimed is:
 1. A magnetic recording device comprising: amagnetic read transducer comprising: a first read sensor, a second readsensor, and a third read sensor, wherein the first read sensor, thesecond read sensor, and the third read sensor are positioned in a downtrack direction with the second read sensor between the first readsensor and the third read sensor, and wherein the first read sensor, thesecond read sensor, and the third read sensor are offset from oneanother in a cross track direction, the down track direction being in aplane that is parallel to an air bearing surface of the magnetic readtransducer and the cross track direction being in a plane that isperpendicular to the air bearing surface; a first middle shield betweenthe first read sensor and the second read sensor, wherein the firstmiddle shield comprises a first top middle shield and a first bottommiddle shield separated by a first insulator; and a second middle shieldbetween the second read sensor and the third read sensor, wherein thesecond middle shield comprises a second top middle shield and a secondbottom middle shield separated by a second insulator, wherein the firsttop middle shield comprises a first antiferromagnetic layer and thefirst bottom middle shield comprises a second antiferromagnetic layer;and wherein the first antiferromagnetic layer is separated from thesecond antiferromagnetic layer by the first insulator; and wherein thefirst top middle shield further comprises a first plurality of layersbetween the first antiferromagnetic layer and the first read sensor andthe first bottom middle shield further comprises a second plurality oflayers between the second antiferromagnetic layer and the second readsensor.
 2. The magnetic recording device of claim 1, wherein themagnetic read transducer is fabricated on a slider of the magneticrecording device.
 3. The magnetic recording device of claim 1, furthercomprising a bottom shield adjacent to the first read sensor, whereinthe first read sensor is between the bottom shield and the first middleshield.
 4. The magnetic recording device of claim 1, further comprisinga top shield adjacent to the third read sensor, wherein the third readsensor is between the top shield and the second middle shield, andwherein the top shield comprises a first magnetic layer, a secondmagnetic layer, a nonmagnetic layer separating the first magnetic layerand the second magnetic layer, and a third antiferromagnetic layerseparated from the third read sensor by the first magnetic layer, thesecond magnetic layer, and the nonmagnetic layer.
 5. The magneticrecording device of claim 1, wherein the first plurality of layers ofthe first top middle shield comprises a first magnetic layer and asecond magnetic layer separated by a nonmagnetic layer.
 6. The magneticrecording device of claim 5, wherein the first bottom middle shield isan antiferromagnetic shield, and wherein the second plurality of layerscomprises a third magnetic layer and a fourth magnetic layer separatedby an additional nonmagnetic layer.
 7. The magnetic recording device ofclaim 1, wherein the second top middle shield comprises a first magneticlayer and a second magnetic layer separated by a nonmagnetic layer, anda third antiferromagnetic layer separated from the second read sensor bythe first magnetic layer, the second magnetic layer, and the nonmagneticlayer.
 8. The magnetic recording device of claim 1, wherein the secondbottom middle shield is a monolithic shield.
 9. The magnetic recordingdevice of claim 1, wherein the second bottom middle shield is anantiferromagnetic shield comprising a first magnetic layer and a secondmagnetic layer separated by a nonmagnetic layer, and anantiferromagnetic layer separated from the third read sensor by thefirst magnetic layer, the second magnetic layer, and the nonmagneticlayer.
 10. The magnetic recording device of claim 1, wherein the firstmiddle shield is configured to be magnetically biased at an angle ofleast zero degrees and not more than fifty-five degrees from the airbearing surface.
 11. The magnetic recording device of claim 1, whereineach of the first read sensor, the second read sensor, and the thirdsensor are flanked on either side in the cross track direction by amagnetic bias structure.
 12. A magnetic read transducer comprising: afirst read sensor; a second read sensor positioned in a down trackdirection from the first read sensor and offset from the first readsensor in a cross track direction, wherein the down track direction isin a plane that is parallel to an air bearing surface of the magneticread transducer and the cross track direction is in a plane that isperpendicular to the air bearing surface; a top middle shield comprisinga first magnetic layer, a second magnetic layer, a nonmagnetic layerseparating the first magnetic layer and the second magnetic layer, andan antiferromagnetic layer, wherein the first magnetic layer is betweenthe first read sensor and the nonmagnetic layer and theantiferromagnetic layer is between the second magnetic layer and thesecond read sensor; a bottom middle shield between the antiferromagneticlayer and the second read sensor, the bottom middle shield comprising afirst additional magnetic layer and an additional antiferromagneticlayer; and an insulator layer between the top middle shield and thebottom middle shield, wherein the antiferromagnetic layer is between theinsulator layer and the second magnetic layer, and wherein theadditional antiferromagnetic layer is between the insulator layer andthe first additional magnetic layer.
 13. The magnetic read transducer ofclaim 12, wherein the first magnetic layer comprises NiFe layersseparated by a CoFeB insertion layer.
 14. The magnetic read transducerof claim 12, wherein the antiferromagnetic layer has a thickness of nomore than one hundred and sixty Angstroms.
 15. The magnetic readtransducer of claim 12, wherein the bottom middle shield furthercomprises a second additional magnetic layer and an additionalnonmagnetic layer separating the first additional magnetic layer and thesecond additional magnetic layer.
 16. A magnetic read transducercomprising: a first read sensor; a second read sensor positioned in adown track direction from the first read sensor and offset from thefirst read sensor in a cross track direction, wherein the down trackdirection is in a plane that is parallel to an air bearing surface ofthe magnetic read transducer and the cross track direction is in a planethat is perpendicular to the air bearing surface; a top middle shieldcomprising a first magnetic layer, a second magnetic layer, anonmagnetic layer separating the first magnetic layer and the secondmagnetic layer, and an antiferromagnetic layer, wherein the firstmagnetic layer is between the first read sensor and the nonmagneticlayer and the antiferromagnetic layer is between the second magneticlayer and the second read sensor; a bottom middle shield between theantiferromagnetic layer and the second read sensor the bottom middleshield comprising a first additional magnetic layer and an additionalantiferromagnetic layer; an insulator layer between the top middleshield and the bottom middle shield, wherein the additionalantiferromagnetic layer is between the insulator layer and the firstadditional magnetic layer, and wherein the antiferromagnetic layer isbetween the insulator layer and the second magnetic layer; and a topshield adjacent to the second read sensor in the down track direction,wherein the second read sensor is between the top shield and the firstread sensor and the top shield comprises top shield magnetic layersseparated by a top shield nonmagnetic layer, and a top shieldantiferromagnetic layer, wherein the top shield nonmagnetic layer isbetween the top shield antiferromagnetic layer and the second readsensor.
 17. The magnetic read transducer of claim 16, wherein the topmiddle shield, the bottom middle shield, and the top shield areconfigured to be magnetically biased at an angle of least zero degreesand not more than fifty-five degrees from the air bearing surface. 18.The magnetic read transducer of claim 16, wherein the bottom middleshield is an antiferromagnetic shield further comprising a secondadditional magnetic layer and an additional nonmagnetic layer separatingthe first additional magnetic layer and the second additional magneticlayer.